The present invention relates to systems and devices for measuring arterial blood pressure. In particular, the invention relates to a two-piece sensor interface assembly for a non-invasive blood pressure measurement device, including a disposable sensing unit.
There has been a continuing need for devices which will measure blood pressure non-invasively and have accuracy comparable to invasive methods. Medwave, Inc. the assignee of the present invention, has developed non-invasive blood pressure measurement devices which are described in the following United States patents: U.S. Pat. No. 5,450,852 entitled CONTINUOUS NON-INVASIVE PRESSURE MONITORING SYSTEM; U.S. Pat. No. 5,640,964 entitled WRIST MOUNTED BLOOD PRESSURE SENSOR; U.S. Pat. No. 5,642,733 entitled BLOOD PRESSURE SENSOR LOCATOR; U.S. Pat. No. 5,649,542 entitled CONTINUOUS NON-INVASIVE BLOOD PRESSURE MONITORING SYSTEM; U.S. Pat. No. 5,720,292 entitled BEAT ONSET DETECTOR; U.S. Pat. No. 5,722,414 entitled CONTINUOUS NON-INVASIVE BLOOD PRESSURE MONITORING SYSTEM; U.S. Pat. No. 5,738,103 entitled SEGMENTED ESTIMATION METHOD; U.S. Pat. No. 5,797,850 entitled METHOD AND APPARATUS FOR CALCULATING BLOOD PRESSURE OF AN ARTERY; U.S. Pat. No. 5,941,828 entitled HAND-HELD NON-INVASIVE BLOOD PRESSURE MEASUREMENT DEVICE; U.S. Pat. No. 6,159,157 entitled BLOOD PRESSURE MEASUREMENT DEVICE WITH SENSOR LOCATOR; and U.S. Pat. No. 6,241,679 entitled NON-INVASIVE BLOOD PRESSURE SENSING DEVICE AND METHOD USING TRANSDUCER WITH ASSOCIATE MEMORY.
As described in these patents, the Medwave non-invasive blood pressure measurement device determines blood pressure by sensing pressure waveform data derived from an artery. As varying pressure is applied to the artery by a sensing chamber, pressure waveforms are sensed by a transducer to produce sensed pressure waveform data. The varying pressure maybe applied automatically in a predetermined pattern, or may be applied manually in a somewhat random fashion. The sensed pressure waveform data is analyzed to determine waveform parameters which relate to the shape of the sensed pressure waveforms. One or more blood pressure values are derived based upon the waveform parameters. The Medwave blood pressure measurement devices include both automated devices for continuously monitoring blood pressure (such as in a hospital setting) and hand-held devices which can be used by a physician, or by a patient when desired. These devices represent an important improvement in the field of non-invasive blood pressure measurement.
The non-invasive blood pressure measurement device is typically comprised of a housing unit with a sensor interface assembly attached thereto. The sensor interface assembly includes electrical circuitry, sensing means, including a transducer, and means for applying variable pressure to the artery. The sensor interface assembly is expensive to manufacture and in particular, the most expensive cost associated with it is the electrical circuitry. A problem arises in the hospital, or a clinical setting, where multiple patients use a limited number of non-invasive blood pressure measurement devices. When the sensor interface assembly becomes contaminated or damaged, it is expensive to have it replaced. Therefore, a sensor interface assembly is needed that is less expensive to replace in the non-invasive measurement device.